In recent years, packet switching technology fast becomes popular and starts to be used in a transport network of an operator. At present, a Multiple Protocol Label Switch (MPLS) network in the packet switching technology usually uses a mesh topology structure, while the transport network usually uses a ring topology structure due to its deployment features. A conventional transport network, for example, a Synchronized Digital Hierarchy (SDH) network, mostly uses the ring topology networking, and implements fast protection switching of services according to the features of a ring network. In SDH times, the application and demand of the ring are rather common, as proved by actual deployment. After the transition of the transport network from the SDH to a packet switching network, since a fiber deployed in advance still has a ring shape, the ring network technology of the packet switching network still has a wide application prospect.
Currently, in the ring network, a link protection tunnel may be established for each link or a node protection tunnel may be established for each node. However, when only the link protection tunnel is established, the node cannot be protected in the case of a node fault. When only the node protection tunnel is established, as shown in FIG. 1, for example, a node protection tunnel T is established for a node B, normal transmission of the services at the node B cannot be implemented when a fault occurs in the link between the nodes A and B.